Chromatin Biology Lab

A central question in the field of chromatin remodeling is how remodelers navigate and manipulate the extensive histone–DNA contacts within nucleosomes to generate diverse chromatin states. Multiple mechanistic models have been proposed, and high-resolution biophysical and structural studies have significantly advanced our understanding to date. Chromatin remodelers are generally categorized into four major families, among which the SWI/SNF and ISWI types exhibit the most prominent biochemical activities. SWI/SNF-type remodelers facilitate histone eviction, engage in diverse modes of transcriptional regulation, often interact with the pre-initiation complex, and can function within nucleosome-depleted regions. In contrast, ISWI-type remodelers primarily regulate nucleosome spacing across gene bodies and are closely linked to nucleosome assembly. Biochemically, these two classes generate markedly distinct outcomes, likely dictated by the manner in which they translocate or apply force to the nucleosomal substrate. Additionally, chromatin remodelers of the CHD-type and INO80/SWR-type exist. CHD-type remodelers (chromodomain helicase DNA-binding proteins) are structurally diverse and functionally versatile, with some members (e.g., CHD1) linked to transcriptional elongation, and others (e.g., CHD4) associated with transcriptional repression and chromatin silencing as part of the NuRD complex. Their chromodomains often enable histone modification–dependent targeting, integrating epigenetic signals with remodeling activity. The INO80/SWR-type is distinct in that it couples ATP-dependent chromatin remodeling with histone variant exchange. The SWR1 complex deposits H2A.Z into nucleosomes near gene promoters and regulatory elements, modulating transcriptional competence and gen